1. Technical Field
The present invention relates to optical discs comprising two information recording layers with respective test areas. The present invention also relates to optical disc apparatuses recording data on such optical discs. The test areas are used in the adjustment of the conditions for driving, for example, the learning of recording conditions.
2. Background Art
In recent years, densities and capacities of optical discs have been increasing, and higher reliability thereof have been becoming important. In order to secure such higher reliability, optical disc apparatuses which record or reproduce data on or from such optical discs perform recording learning in order to obtain recording and reproduction conditions for optical discs (cf. Japanese Laid-Open Publication No. 2001-338422).
Recording learning is a series of operations to optimize the pulse conditions of laser pulses which strike an optical disc. The pulse conditions include, for example, the power levels of the laser pulses which strike the optical disc during recording, the conditions for timing and lengths of the laser pulses, and the like.
Other techniques under active development include providing an optical disc with an additional semitransparent information recording layer located in front of an original information recording layer in the direction of optical beams used in recording and reproduction, and thereby doubling the recording capacity of the optical disc. Such a dual-layer optical disc also requires recording learning. Operations of learning recording conditions are performed at the front layer (hereinafter, L1 layer) and the back layer (hereinafter, L0 layer) in the optical beam direction (cf. Japanese Laid-Open Publication No. 2000-311346).